Glow plugs are used in internal combustion engines utilizing diesel fuel to facilitate starting. In cold weather, electrical energy supplied to a glow plug for each cylinder ignites the diesel fuel within each engine cylinder. Once the engine is in operation and becomes heated ignition of the diesel fuel occurs automatically and the electrical energy to the glow plug is discontinued. Examples of glow plugs may be found in U.S. Pat. Nos. 4,112,577; 4,087,904; and 3,749,980.
To prevent pressure within engine cylinders from being dissipated each glow plug is sealed internally so that pressure within an engine cylinder will not escape through the glow plug. Accordingly within each glow plug there is a pressure tight seal between the heater assembly its protective shield and the outer shell of the plug. This pressure tight seal has been provided by swaging or cold working the elements together and the use of a silver solder. The disadvantages of these types of seals are that they are expensive to make.